LAYER ingredients in slow cooker in the following order: cabbage, beets, carrots, parsnip, onion, garlic, beef, tomatoes with juice, broth, lemon juice, sugar and pepper.
Cover and cook on LOW 7 to 9 hours or until vegetables are crisp-tender.
Season with additional lemon juice and sugar, if desired.
Dollop with sour cream and garnish with parsley, if desired.